I'm not very familiar with cooling, so I have some followup questions. Hope you got time to give some more clearence

I don't think it's air flow. I have 2 extra fans in the cabinet, and the temp on my gfx card is ood.

I only have one fan on the Zalman cooler, so that might not be it.

The only logical explanation I guess is left, is either the thermal paste or the cooler properly seated. Before I start yanking out the cooler to change the thermal paste and figure out if it's correctly seated; Is there any specific thermal paste I should buy?

And my second question: What's PSU/motherboard got to do with it? My motherboard is a ASUS m4a785td-m evo, and my PSU is a 650Watt Corsair TX. Could those be the problem?

IC Diamond is the best, but expensive. Arctic Silver 5 is old, cheap, popular, and effective. I would suggest getting some Articlean as well, it is cheap and makes removing old TIM extremely quick and easy, and removes more than 90% alcohol and hard scrubbing, and it's only $7 and you only use a few drops each time.

Underpowering a component can cause overheating, which usually happens with some backstreet communist Chinese off brand power supply that any second year American electrical engineering student could make. But with that PSU it's not a problem.

What are your ambient temps? Anything above about 75°F/24°C and you should look at a closed liquid cooler.